Improvement in school-globes



` 'UNITED' STATES- PA-TENT OFFICE.

JOHN n. AGN-nw, "or Mnnonn'ssnnn. rnNNsYLvANIn IMPROVEMENT IN SCHOOL-GLOBES;

.Specification formingzpart of Letters Patent No. 38,875,1dated June 16, 1863.

To all, whom zt-may eoncerml I Be it known that l, JoHNlt. AGNEW, of Mercersburg, in.the county of Franklin and 4State of Pennsylvania, have invented a new and useful Improvement in School-Globes and Ido hereby declare that the -following isa full, clear, and exact description of Athe same, reterence being had to the accompanying drawings, forming a part'of this specification, in

which- Figure l represents a fron-t elevation of my invention, Fig. 2 is a vertical central sectionv of the same.

Similar letters of reference in both views indicate corresponding parts.

The object of this invention is to represent the periodical change taking place in theposition of the earth in the universe, which is made apparentby the precession of the equinoxes, and also the apparent change Iof the position of' the stars in relation to the earth,

- which is observed by the changes in the visible heavens from night to night, or from month to month. I l

The invention consists in the application to acelestial globe ot' a transparent case, having depicted on its surface the same lines and the same constellations which are depicted on the aforesaid celestial globe, and being connected to the saine by means of pivots, inserted into the ecliptic poles oi' the inner globe, and passing through the ecliptic poles of the transparent case in such a manner that by moving said transparent case or the` globethe recession of the ecliptic or the precession ofthe equinoxes, and consequently the true relation of the lines and points of ay celestial globe toward-eaeh other and toward the observer on the earth can be illustrated.

It consists, further, in constructing said outer case of some iiexible' material and providing .it with a certain number of hour circles or meridians. in such a mannenthat by adjusting `said meridians the daily rising and setting ot' the stars can -be illustrated.

To enable those skilled in the art to make and use my inventiomI will proceed to describe it with reference to the drawings.

Arepresents a celestial globe, suspended, by means of pivots a, from theipoles ofthe eclip-A tic b. The equator c bisects the ecliptic at two points, which in the present time are situated in the constellations 1)isces7and Virgo, 7

but which some two thousand years ago were It is obvious that simultaneously with the precession of' the equinoxes the poles of the equator, or'thoscp'onin 'the heavens generally designated as the north and south pole,

will describe circles around the poles of the ecliptic, or our north and south poles, instead of retaining their positions in the saine eonstellations, will travel from one constellation t0 the other. In the present time our north pole coincides nearly with a star in the tail of 'U rsa Minor, and this staris commonly called north star,7 but from some five thousand years ago the star a, in the constellation Draco has been the north star, and in about twelve thousand years'from now the stan 'Vega7 in the constellation Lyra will be' the north star. These changes are' illustrated by the application of the case B, whichfis made of'some transparent materiahand which surrounds the globe A, so that the same can either be rotated within the case or the case rotated around the globe. This ca seis marked with the saine `lines and with the same con'- stcllations as thefglobe, and it is connected to said globe so that the ecliptic of the case covers the 'ecliptic of the` globe. ing to the case I a rotary motion around the globe, the equinoxes ofthe case pass through every point of the ecliptic on the globe, and

the preccssion of the equinoxes can thus be illustrated. vAt the same time the north and south poles, marked on the case, describe circles around the eeliptic poles of the globe, and

it can be observed at a glance which stars will be thc north or south stars, and at what time. ,By ,moving the ease it will be noticed that after about one-halt' ot' the great period the north pole will be inthe neighborhood of the star VVega in Lyra. By these means the position of the equinoxes and of-the north and south poles can always be corrected and proporly illustrated. v The case B serves also to determine the visible partsof thc'heavens from night to night, or the-daily rising and setting of the stars. To accomplish this purpose the solid globe A ismarked with the outlines ol'a ly impartof the equator. The large brass circle C will represent the rational horizon of al1- persons living on the equator of the earth. `Onehalf or more of the folds or ribs d are then `fastened down by holes in the tapes (It, catching in the hook d*,and if theinner globe is taken oftit's pivots the folding caserepresents the sk y above the observer at night.- By unfastening one of the folds on the east side and drawing down a fold on the other, or west side, the rising or sett-ing or' the stars is represented. The rising of thefold on the east side with its stars represents their rising, and the folding of it down on the West side their setting. By

making the horizon adjustablethe folding case can be adapted to diierent-localities on the globe, but its operation will be essentially the same as above described.

Having thus fully described my invention, what I claim as new, and desire .tol secure by Letters Patent, is-' l. The'arrangement of the case B, in combination with a celestialor with a terrestrial globe, "constructed and `arranged substan- Ytiallyas and .for the purpose herein shown and described. p l 1, v

2. The arrangement of the folds "or ribs d, in; the tlexibllehcase B, in combination with the horizon C and globe A, constructed and operating` substantially as and for therpurpose specified. JOHN R. AGNEW. Witnesses:

l. HAMM-AN, LEWIS SHOEMAKER. 

